This invention relates to LED lighting circuits. More specifically this invention relates to a circuit for providing improved operation of an LED lighting device.
LED lighting as an energy efficient lighting source is becoming more and more popular world-wide. Several ways exist regarding how to successfully operate and dim LED devices. In particular, typically line voltage is AC or alternating current voltage where the voltage and current are represented by a sine wave. One circuit that can be used to operate and dim LED utilizes a rectifier and AC to DC converter in association with a PWM device to provide dimming.
In an alternative embodiment applicant eliminated the AC to DC converter and need for a PWM device through conditioning the AC current directly provided to the LEDs. This is shown in applicant's U.S. Pat. No. 8,373,363 that is incorporated in full herein. While effective at operating and dimming, problems remain. During analog operation there are times during operation where current exists at zero cross for extended periods of time. For certain operations light is desired during this period. As one example, some flicker indexes put out by specification makers focus, not just on frequency of the AC sine wave, but also on the drop in current from peak to the valley of the sine wave. In another embodiment, in agricultural and horticulture applications applicant has found that low levels of green light can be beneficial to animal and plant growth and should be used in combination with other colored lighting to optimize growth in animals and plants. Thus a need exists in analog circuits to reduce the gap between peak current and the current at a valley to improve dimming properties and provide additional functionality to a lighting device.
Therefore, a principle object of the present invention is to improve dimming functionality of an AC analog circuit.
Yet another object of the present invention is to improve functionality on an AC analog circuit.
These and other object, feature and advantages will become apparent from the specification and claims.